Are You Confident of the Diagnosis?

What you should be alert for in the history

Sudden onset of a painful vesicular rash in a patient with a preexisting skin condition should alert you to the diagnosis of eczema herpeticum (EH).

Characteristic findings on physical examination

Characteristic findings on physical examination typically include vesicles and/or pustules that become hemorrhagic and crusted and eventually evolve into monomorphic punched out erosions (Figure 1, Figure 2). These generally occur in the setting of a background dermatosis. The eruption may coalesce into large denuded areas that can be secondarily infected. Patients typically have associated fever and malaise.

Figure 1.

Typical vesicles and punched out erosions on face and torso.

Figure 2.

Typical vesicles and punched out erosions on hand and forearm.

Expected results of diagnostic studies

Diagnosis can be confirmed by direct fluorescent antibody (DFA), polymerase chain reaction (PCR), Tzanck smear, and viral culture. Biopsy is generally not necessary to make the diagnosis. Histopathologic changes are consistent with Herpes infection with ballooning degeneration of keratinocytes and multinucleated cells exhibiting viral cytopathic changes.

What is the Cause of the Disease?

Etiology

Pathophysiology

Mutations in filaggrin have clearly been associated with atopic dermatitis and atopy. Recent studies have indicated that specific filaggrin mutations may confer increased suceptibility to EH.

Systemic Implications and Complications

Systemic implications/complications include viremia (especially in neonates and immunocompromised patients), secondary bacterial Infection/septicemia, and HSV keratitis. Because of the potential scarring and blindness, ophthalmology consultation is indicated with any suspicion of possible eye involvement.

Treatment Options

Systemic Antivirals

Acyclovir

Neonatal - intravenous route; 60mg/kg/day in three divided doses for a minimum of 14 days

Pediatric - intravenous route initially; May be transitioned to oral medication once stable

-15mg/kg/day in 3 divided doses for 5-7 days

-1200mg/day in 3 divided doses for 7-10 days; maximum 80mg/kg/day

Adults - Oral route; 400 mg orally 5x daily x 10 days

-Immunocompromised: intravenous route initially; May be transitioned to oral medication once stable

-Less than 12 years old: 30mg/kg/day in 3 divided doses for 7-14 days

-12 years old and older: 15mg/kg/day in 3 divided doses for 7-14 days

Valacyclovir

-Adults - 1000mg twice daily for 10 days

Foscarnet is the treatment of choice in immunocompromised adult patients with resistance to acyclovir -40 mg/kg IV Q8-12hr x 2-3weeks (maintain adequate hydration prior to and during treatment)

Note: Suppressive therapy is not generally necessary as recurrences are not common. Any recurrences of EH, however, should prompt consideration of prophylactic therapy

Optimal Therapeutic Approach for this Disease

If EH is suspected, early empiric treatment should be initiated immediately. For pediatric patients, initial intravenous therapy is the standard of care but may be transitioned to oral therapy once stable. Oral therapy may be considered in older pediatric patients with less severe and more localized disease. For Immunocompromised patients, initial intravenous therapy is the standard of care but may be transitioned to oral therapy once stable. If a patient is known to have acyclovir resistant herpes, Foscarnet is the treatment of choice

Patient Management

All patients require close follow-up to ensure adequate response to treatment. Patients not responding to typical outpatient medical therapy may require hospitalization for intravenous therapy

Unusual Clinical Scenarios to Consider in Patient Management

EH can be complicated by systemic viremia, especially in neonates/infants. Because of the increased morbidity and mortality of disseminated viral infection, management with hospitalization for systemic intravenous antivirals is the standard of care in the pediatric population. Older children may be transitioned oral medication once stable. Other possible complications that should not be missed include herpes keratitis and secondary bacterial infections and septicemia

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